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Questions and Answers
What is the primary immunoglobulin produced in a Type I hypersensitivity reaction?
Which of the following is NOT a characteristic of Type II hypersensitivity?
What happens during anaphylaxis in Type I hypersensitivity?
Which of the following conditions is an example of a Type III hypersensitivity reaction?
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Type IV hypersensitivity is characterized by which of the following?
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Which of the following is an example of a condition that can result from Type II hypersensitivity?
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What triggers the immune response in Type III hypersensitivity?
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In which type of hypersensitivity is the principal mechanism macrophage and T-cell interaction?
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Which of the following is a common allergen associated with Type I hypersensitivity?
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Cross-reactivity between exogenous and endogenous tissues is a feature of which hypersensitivity type?
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Which type of hypersensitivity is primarily mediated by IgE antibodies?
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What is the main cause of tissue injury in Type III hypersensitivity reactions?
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Which of the following is a delayed reaction seen in Type IV hypersensitivity?
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What is a common feature of Type II hypersensitivity reactions?
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Which condition is an example of a Type I hypersensitivity reaction?
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What is the primary immune response mechanism involved in Type II hypersensitivity?
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Which statement about Type IV hypersensitivity is true?
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Which of the following is associated with immune complex deposition in Type III hypersensitivity?
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In Type II hypersensitivity, which of the following is a potential clinical manifestation?
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Which of these examples is MOST likely a consequence of a Type III hypersensitivity reaction?
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Study Notes
Hypersensitivity
- Hypersensitivity is an increased immune response towards an antigen causing undesirable clinical effects.
- The four types of hypersensitivity reactions often occur together.
Type I - Immediate Hypersensitivity, Atopy
- IgE is produced in response to an allergen, instead of IgG
- Mast Cell Degranulation: Mast cells release histamine when IgE binds to them
- Histamine Release: Triggers an allergic reaction
-
Allergens: Harmless substances that cause an allergic response
- Examples:
- Shellfish
- Pet Dander
- Dust Mites
- Peanuts
- Latex
- Insect Venom
- Examples:
- Anaphylaxis: Systemic Type I response
Type II - Cytotoxic Reactions to Self-Antigens
- Immune response directed against one's own tissues
-
Complement Activation, Agglutination, Phagocytosis: These processes destroy cells.
- Examples:
- Hemolytic Diseases of the Newborn
- Myasthenia Gravis
- Examples:
-
Cross-Reaction between Exogenous and Endogenous Body Tissues: Immune response to an exogenous antigen triggers a response against similar endogenous antigens.
- Examples:
- Hemolytic Streptococci / Mitral Valve Disease
- Guillian-Barre Syndrome
- Examples:
Type III - Immune Complex Diseases
- Antigen-antibody complexes form and deposit around small blood vessels.
-
Complement Cascade, Acute Inflammation, Tissue Injury: These processes result from complex deposition.
- Examples:
- Rheumatoid Arthritis
- Nephritis
- Pericarditis
- Vasculitis
- Systemic Lupus Erythematosus (Cell nucleus is the antigen)
- Examples:
Type IV - Cell-mediated Immunity
-
Delayed Reaction to Allergen: Takes 48-72 hours for symptoms to appear, as it involves a macrophage to T-cell reaction.
- Examples:
- Transplant Rejections
- Delayed Contact Dermatitis (e.g., poison ivy)
- Examples:
Hypersensitivity
- Hypersensitivity is an increased immune response to an antigen that causes negative clinical effects
- The four types of hypersensitivity do not necessarily occur in isolation
Type I - Immediate Hypersensitivity, Atopy
- IgE is produced instead of IgG
- Mast cell degranulation occurs, releasing histamine
- Allergens are normally harmless substances that cause allergic responses
- Examples include: shellfish, pet dander, dust mites, peanuts, latex, insect venom
- Anaphylaxis is a systemic Type I response
Type II - Cytotoxic reactions to self-antigens
- Immune response to one's own tissues
- Complement activation, agglutination, and phagocytosis occur
- Examples: Hemolytic diseases of newborn, Myasthenia gravis
- Cross-reaction between exogenous and endogenous body tissues
- Examples: Hemolytic streptococci / mitral valve disease, Guillian-Barre syndrome
Type III - Immune Complex Diseases
- Antigen-antibody complexes deposit around small blood vessels
- This causes complement cascade, acute inflammation, and tissue injury
- Examples: Rheumatoid arthritis, nephritis, pericarditis, vasculitis, systemic lupus erythematosus (cell nucleus is the antigen)
Type IV - Cell-mediated immunity
- Delayed reaction to allergen, typically 48-72 hours
- Based on macrophage to T-cell interactions, which take time to occur
- Examples: Transplant rejections, delayed contact dermatitis (e.g., poison ivy)
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Description
Test your understanding of the various types of hypersensitivity reactions. This quiz covers the mechanisms, examples, and clinical implications of immediate and cytotoxic hypersensitivity. Enhance your knowledge on how the immune system can overreact to harmless substances and self-antigens.
